Modern trends of using innovative nanoparticle approaches for immune-based osteosarcoma therapy.

The most prevalent primary malignant bone tumor is osteosarcoma, with a frequency of 3-5 cases per million per year and approximately 3000 new cases in the world every year. Osteosarcoma is a disease that mostly affects children and adolescents. Effective treatment is through surgical resection with multi-agent chemotherapy; the survival rate of the patient with localized disease is only 60-70 %, whereas with metastasis or recurrence of disease, it becomes less than 30 %. The causes of treatment failure are often associated with drug resistance, the metastasis of the tumor, and the lack of effective treatment methods. The necessity for the development of new methods is urgent. Within the past few years, immunotherapies, including immune checkpoint inhibitors and adoptive T-cell therapy, have been tested in osteosarcoma, although their clinical efficacy has been constrained by immune evasion in the tumor and inefficacy. Immunomodulatory nanoparticles have emerged as a promising solution to these challenges by modulating immune responses and targeting the delivery of cancer cells. These nanoparticles can activate or suppress immune pathways, in addition to providing the benefits of tumor targeting and immune monitoring. They are currently used to enhance the effectiveness of chemotherapy, boost anti-tumor immunity, and counteract drug resistance. Instead of covering a simple carrier with chemotherapeutic properties, this review addresses nanoparticles based on their direct or indirect immunomodulatory action, which involves reprogramming of immune cells, altering checkpoints, and inducing immunogenic cell death.